Roll-forming is used with advantage in the fabrication of a number of variously configured metal objects. In a roll-forming process, a sheet of metal, typically steel, is continuously fed through a series of roller dies which progressively bend, stretch and shape the sheet into a body having a preselected cross-sectional profile. Roll-forming steps can be readily incorporated into continuous fabrication processes, and such techniques are widely used for the fabrication of various automotive components. Roll-forming processes, with a few notable exceptions, generally cannot be used to shape the longitudinal dimension of articles, and this does limit the utility of roll-forming techniques to some degree.
Other metal forming processes such as bending, stamping, forging, hydroforming, die-forming, post-forming and the like can be utilized to shape metal articles. Also, processes such as heat treating, nitriding, quenching and tempering may be employed to control hardness or other properties of metal articles. As will be explained hereinbelow, the present invention combines roll-forming with other metal shaping and treating processes to provide an integrated, continuous system and process for producing shaped metal articles.
Automobiles and other motor vehicles generally include a number of protective members therein such as bumper beams and side intrusion beams. These members must be high strength, and are preferably light in weight and low in cost. Bumper and intrusion beams are, as a consequence, often fabricated from folded, sheet steel members having a cross-sectional profile which may be of a C shape or of a closed, boxlike or circular cross section. Ideally, such members are relatively light in weight, of high strength, and low in cost. As will be detailed hereinbelow, one aspect of the present invention provides a continuous manufacturing process and apparatus for producing particularly configured high strength steel items such as bumper beams and side intrusion bars for motor vehicles. The method and apparatus of the present invention rely upon a combination of roll-forming and other processing operations carried out on a continuous basis utilizing coiled sheet steel. Unlike many roll-forming processes, the process of the present invention can be used to fabricate relatively complex shapes. These and other details of the present invention will be apparent from the drawings, discussion and description which follow.